Abstract
Rationale.Classic psychedelics are currently being studied as novel treatments for a range of psychiatric disorders. However, research on how psychedelics interact with other psychoactive substances remains scarce.ObjectivesThe current study aimed to explore the subjective effects of psychedelics when used alongside cannabis.MethodsParticipants (n = 321) completed a set of online surveys at 2 time points: 7 days before, and 1 day after a planned experience with a serotonergic psychedelic. The collected data included demographics, environmental factors (so-called setting) and five validated questionnaires: Mystical Experience Questionnaire (MEQ), visual subscales of Altered States of Consciousness Questionnaire (ASC-Vis), Challenging Experience Questionnaire (CEQ), Ego Dissolution Inventory (EDI) and Emotional Breakthrough Inventory (EBI). Participants were grouped according to whether they had reported using no cannabis (n = 195) or low (n = 53), medium (n = 45) or high (n = 28) dose, directly concomitant with the psychedelic. Multivariate analysis of covariance (MANCOVA) and contrasts was used to analyse differences in subjective effects between groups while controlling for potential confounding contextual ‘setting’ variables.ResultsThe simultaneous use of cannabis together with classic serotonergic psychedelics was associated with more intense psychedelic experience across a range of measures: a linear relationship was found between dose and MEQ, ASC-Vis and EDI scores, while a quadratic relationship was found for CEQ scores. No relationship was found between the dose of cannabis and the EBI.ConclusionsResults imply a possible interaction between the cannabis and psychedelic on acute subjective experiences; however, design limitations hamper our ability to draw firm inferences on directions of causality and the clinical implications of any such interactions.
Highlights
Psychedelics are being extensively researched with respect to their potential usage in clinical settings as an addition to psychotherapy for treating various mental health disorders
While 654 participants have signed up for the survey, 321 of them have completed all of the time points analysed in the current study; only this subset has been included for the final analysis
The current study investigated the effects of concomitant cannabis use on the subjective quality of a psychedelic experience across a spectrum of measures including mystical type, visual, challenging, ego-dissolution and emotional breakthrough domains
Summary
Psychedelics are being extensively researched with respect to their potential usage in clinical settings as an addition to psychotherapy for treating various mental health disorders. A growing body of evidence suggests their efficacy for addressing conditions such as depression (Carhart-Harris et al 2016, 2018a), depressive and anxiety symptoms in patients with terminal cancer (Griffiths et al 2006, 2016; Ross et al 2016), obsessive–compulsive disorder (OCD) (Moreno et al 2006) or addiction (Johnson et al 2014; Bogenschutz et al 2015) These studies suggest that critical mediators of the efficacy of psychedelic-assisted psychotherapies lie in the acutely experienced psychedelic state (Roseman et al 2018). For an in-depth analysis of predictors of psychedelic response, please refer to the study by Haijen et al (2018)
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